Lava lamps have been a popular decoration and light fixture since they were invented in the 1960s. Their hypnotic motion and colorful blobs captivate viewers. But what causes the otherworldly movement inside a lava lamp? The liquid inside lava lamps has some special properties that create the distinctive visual effect.
The History of Lava Lamps
Lava lamps were invented in 1963 by British accountant Edward Craven Walker. He originally called them Astro Lamps and patented them in 1965. The original design used mineral oil, paraffin wax, and carbon tetrachloride as the key ingredients to create the lava effect.
The rising blobs seen in lava lamps are caused by the phenomenon of “density difference.” Walker discovered that when certain materials are combined, they heat and cool at different rates. This causes some of the blobs to become more buoyant than the surrounding liquid, rise to the top, then sink down again as they cool off.
Walker’s Astro Lamp design was popular in the 1960s and he made a business selling them. The lamps were given the name “lava lamp” by Craven’s American business partner who began manufacturing them under the Lava brand name in the late 1960s to appeal to the American market.
How Lava Lamps Work
Modern lava lamps use a combination of colored wax and clear mineral oil as the two key liquids that create the motion effect. Here is an explanation of how the components interact inside a lava lamp:
- The base of the lamp contains colored wax blobs of varying size and shape.
- Above the wax sits a clear and colorless mineral oil liquid.
- A light bulb at the bottom heats the wax.
- As the wax heats up, its density decreases and it becomes more buoyant than the surrounding liquid.
- The buoyant, low density wax blobs then float up through the mineral oil.
- When they reach the top, the blobs begin to cool and sink again.
- This cycle of rising, cooling, and sinking wax creates the constant motion that mesmerizes lava lamp viewers.
Additional features like the elongated lamp shape, glass chimney, and light effects add to the visual spectacle, but it is the density difference between hot wax and room temperature oil that creates the distinctive lava movement.
The Chemistry Behind Lava Lamps
Several scientific principles explain how lava lamps work their magic including:
Thermal Expansion
Thermal expansion causes the wax blobs to expand when heated. As their volume increases, their density decreases and they become more buoyant than the surrounding liquid.
Convection Currents
The cycling of heating and cooling the wax creates convection currents – the circular movement of wax rising and sinking inside the lamp.
Phase Changing
The wax undergoes phase changing between solid and liquid form as it melts from the heat and solidifies when cooling at the top. This allows the wax to change density states.
Density Difference
The differing densities of the hot wax and room temperature oil are what create the lava effect as the wax blobs rise and sink.
Surface Tension
Surface tension between the two liquids causes the wax blobs to hold together in unique shapes as they rise and sink through the oil.
Understanding these scientific concepts helps explain the mesmerizing light show created inside every lava lamp.
Lava Lamp Liquid Ingredients
The exact ingredients inside lava lamps have changed over the years as different companies manufactured them and safety regulations evolved. Here are some of the most common substances used in the two key lava lamp liquids:
Wax
- Mineral oil
- Paraffin wax
- Microcrystalline wax
- Beeswax
Mineral Oil
- Light mineral oil
- White mineral oil
- Paraffin oil
- Silicone oil
Most lava lamp recipes use a combination of waxes to get the ideal density and melting point for optimal lava movement. The clear oil is typically a light, odorless mineral oil or silicone oil.
How to Make Your Own Lava Lamp
It’s possible to make your own DIY lava lamp at home using simple household ingredients. Here are the basic steps:
- Use an empty plastic bottle for the lava lamp vessel.
- Add vegetable oil, baby oil, or corn syrup for the clear liquid base.
- For the “lava”, melt beeswax, crayons, or candle wax and add food coloring.
- Drop in the melted colored wax blobs into the oil base.
- Cap the bottle securely.
- Heat the bottle with a light bulb or submerge it in hot water to get the lava flowing!
While not as elegant as real lava lamps, homemade versions can still provide mesmerizing results as you watch the wax blobs move around endlessly. Just be careful with using heat sources near flammable oils.
Troubleshooting Lava Lamps
Sometimes lava lamps can stop working properly and the motion effect ceases. Here are some common issues and how to get your lava lamp flowing again:
| Issue | Solution |
|---|---|
| No motion | Gently shake lamp to re-blend wax blobs and oil. Check light bulb. Let lamp run for 2+ hours. |
| Weak lava motion | Add more wax chunks. Clean bottle residues. Replace old wand. |
| Wax build up | Gently warm bottle to re-melt wax. Filter oil to remove contaminants. |
| Cloudy appearance | Change oil and wax to fresh liquids. Check for leaking seals. |
Be patient, run your lava lamp for a few hours, and try gently agitating the bottle to work out any stuck blobs. Using fresh wax and oil ingredients can rejuvenate old lamps.
Fun Facts About Lava Lamps
- Over 50 million original Lava brand lava lamps have been sold since 1965.
- The lamps are manufactured from parts sourced from over 15 different countries.
- Each wax blob inside a lava lamp can take 30-45 minutes to complete one full cycle from bottom to top and back down.
- There are thousands of different wax blob shapes flowing around inside each active lava lamp.
- Lava lamp contents are recyclable. The wax can be re-melted and the glass reused.
- Warning labels caution against operating Lava brand lamps above 40°C (105°F) as the wax can overheat and release smoke.
- Double motion “Glitter lamps” were introduced in the 1990s which add glitter to the oil for a sparkling effect.
Conclusion
Lava lamps have delighted fans for over 50 years with their unique display of endlessly morphing colored wax blobs. The effect is created by the density difference between hot melted wax and cool mineral oil. Understanding the science behind lava lamps allows you to troubleshoot issues and even create your own homemade version. While the original ingredients may have changed, the hypnotic motion of modern lava lamps is still powered by the same forces of heat, density, and buoyancy that Edward Craven Walker discovered in 1963.